Transition metal complexes are of considerable interest in the modification of nucleic acids. Certain nickel(II) complexes are of particular interest due to their carcinogenic activity. The goals of this proposal are to understand the chemical events related to nickel-mediated DNA damage and to investigate whether nickel peptides might be used as highly specific DNA recognition and modification agents. The specific aims of this proposal are to: 1) determine sequence specificity and the site of transition metal coordination compounds interaction with DNA, 2) mimic physiological conditions using peptide ligands in order to explore metal toxicity, and 3) generate peptide libraries to study DNA specificity.